The present invention relates to apparatus and a method for pyrolysis of a primary material, such as coal, preferably utilizing a second material such as hot char as a heat source, and more particularly is directed to apparatus for flash pyrolysis of particulate coal, and utilizing particulate hot char, employing components having a geometry or shape which affords simpler and more feasible "scaling up" of the apparatus design for commercial application, and which also provides additional advantages.
For a process that is essentially plug flow in nature, that is, wherein the reactor components are mixed in a pyrolysis chamber in a radial rather than in an axial direction, and the resulting mixture has uniform composition and properties at any cross section of the reactor, selection of the geometry of the apparatus is not critical for purposes of "scaling up" for commercial application. For example, if the residence time of the materials in a pyrolysis reactor is a function of the length of the reactor, throughput is increased by increasing the cross section of the reactor. Thus, in the period of time between rapid heating, that is mixing of the particulate materials in the reactor and solids separation, the selection of a particular geometry for the reactor cross-section is relatively unimportant. However, the rapid heating and solids separation operations, are not plug flow in nature.
If a circular geometry is selected for the cross section of the reactor, a reactor design could be selected of the type disclosed and claimed in my application Ser. No. 633,898, filed Nov. 20, 1975, which is a continuation of Ser. No. 449,073 filed Mar. 7, 1974, now abandoned, in the form of a coaxial jet mixer for mixing and pyrolysis of a primary material source such as particulate coal, utilizing a secondary material such as particulate char as a heat source, a tubular reactor and a conventional cyclone receiver. In an apparatus of this type a coal stream is introduced through an inlet such as a nozzle into a fluidized annular stream of char, and the turbulent mixture pyrolyzed in the tubular pyrolysis reactor. As such design is scaled up to higher throughputs, the mixing time is increased and the separation time in the cyclone is increased. Although this can be compensated to some degree by permitting multiple injection systems and multiple cyclones or collectors, the benefits of this additional apparatus is marginal and the overall symmetry is disrupted.
It is an object of the present invention to provide a novel apparatus and method for pyrolysis of particulate materials, such as coal.
A further object of the present invention is to provide apparatus and a method of such type which involves the use of non-circular or non-tubular material feeding and pyrolysis reactor components.
A still further object of the present invention is to provide apparatus and a method of the above type employing a novel pyrolysis products separator design providing rapid separation of solids from gases, and incorporating means in such separator for collecting and withdrawing pyrolysis gases.